Re: [Qemu-devel] [PATCH] hw/acpi: fix Q35 support for legacy Windows OS

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Mar 07, 2016 at 03:21:44PM +0200, Marcel Apfelbaum wrote:
> On 03/07/2016 02:36 PM, Michael S. Tsirkin wrote:
> >On Mon, Mar 07, 2016 at 01:06:43PM +0100, Igor Mammedov wrote:
> >>On Sun,  6 Mar 2016 14:17:56 +0200
> >>Marcel Apfelbaum <marcel@redhat.com> wrote:
> >>
> >>>Legacy Windows operating systems like Windows XP and Windows 2003
> >>>require _DIS method to be present for all interrupt links.
> >>>
> >>>PC machines already have a no-op implemented for GSI links, add
> >>>it also in Q35.
> >>Maybe I don't see but only LINKS has no-op _DIS, the rest of
> >>links have _DIS that does something. According to spec
> >>_STA must return disabled status after _DIS has been called.
> >
> >A no-op _DIS is OK as long as the interrupt can not be disabled.
> >Marcel, how about a comment explaining this?
> 
> Sure, I'll add a comment and re-post.
> 
> >
> >BTW, going over it again:
> >- we really need to set separate UIDs for them, might
> >   be a good idea to fix that, might it not?
> 
> Absolutely (in my opinion), Igor is OK if I'll submit a patch for it?
> Since we're getting rid of old Q35 machines we don't care about compatibility here.

ACPI tables are guest code, so we need not worry about compatibility
anyway.

> >-
> >     method = aml_method("_SRS", 1, AML_NOTSERIALIZED);
> >     aml_append(method, aml_create_dword_field(aml_arg(0), aml_int(5), "PRRI"));
> >     aml_append(method, aml_store(aml_name("PRRI"), reg));
> >     aml_append(dev, method);
> >
> >should this be serialized as it creates a local name (PRRI)?
> >
> 
> I'll let Igor answer this.
> 
> Thanks,
> Marcel
> 
> >>
> >>>
> >>>Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> >>>---
> >>>
> >>>Hi,
> >>>
> >>>I tested this patch with WinXP and Win 2003, but also with Win 10, and Fedora.
> >>>This solves a BSOD early in the setup process.
> >>>
> >>>WinXP/2003 can be tested using:
> >>>      -device piix3-ide,id=legacyide \
> >>>      -drive file=winxp-q35.qcow2,if=none,id=disk -device ide-hd,drive=disk,bus=legacyide.0 \
> >>>      -drive file=xp_sp3.iso,if=none,id=cdrom -device ide-cd,drive=cdrom,bus=legacyide.1
> >>>
> >>>Please note that you have to use the piix3-ide because Win2003 (and probably XP)
> >>>does not have Q35 AHCI drivers inbox.
> >>>
> >>>Thanks,
> >>>Marcel
> >>>
> >>>  hw/i386/acpi-build.c | 3 +++
> >>>  1 file changed, 3 insertions(+)
> >>>
> >>>diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> >>>index 52c9470..4c66568 100644
> >>>--- a/hw/i386/acpi-build.c
> >>>+++ b/hw/i386/acpi-build.c
> >>>@@ -1509,6 +1509,9 @@ static Aml *build_gsi_link_dev(const char *name, uint8_t uid, uint8_t gsi)
> >>>
> >>>      aml_append(dev, aml_name_decl("_CRS", crs));
> >>>
> >>>+    method = aml_method("_DIS", 0, AML_NOTSERIALIZED);
> >>>+    aml_append(dev, method);
> >>>+
> >>>      method = aml_method("_SRS", 1, AML_NOTSERIALIZED);
> >>>      aml_append(dev, method);
> >>>